Glucose meters are an example of unit use devices, meaning that when a sample is assayed, a new reagent strip (the unit) has to be used. Some years ago, unit use device manufacturers argued that QC is less important for their products because of among other reasons, a more rigorously controlled manufacturing process was used.
I have been doing some work with glucose meters and note that at least twice this year there have been recalls for reagents strips from two different manufacturers. Here are my reasons for why these recalls continue to happen.
- Vendors that supply raw materials have provided different lots from those used to design and evaluate the original reagent strip.
- Vendor processes have changed.
- The glucose meter manufacturer processes have changed
- The process used to release reagent strip lots is imperfect. It is not as rigorous as a full blown method comparison and the parameters measured may not reflect all aspects of performance.
- The process parameters limits may not be correct.
- Some key variables may not be measured.
- The sample size may not be adequate.
- And last but not least people make mistakes!!!
As someone who worked for manufacturers, the recall sequence was usually: our service department received complaints from customers, these complaints were verified in-house, and a recall was initiated.